#!/usr/bin/env python
# vim:fileencoding=utf-8
from datetime import datetime, timezone

from calibre.web.feeds.news import BasicNewsRecipe


class NoArticles(Exception):
    pass


class Fokus(BasicNewsRecipe):
    title = 'Fokus'
    main_url = 'https://www.fokus.se'
    description = "The last 7 days of news and articles from the Swedish current-affairs magazine 'Fokus'"
    encoding = 'utf-8'
    __author__ = 'Henrik Holm (https://github.com/h-holm)'
    language = 'sv'
    ignore_duplicate_articles = {'title', 'url'}
    masthead_url = 'https://cdn.fokus.se/app/uploads/fokus/2022/05/12214931/fokus-logo.svg'
    no_stylesheets = True
    compress_news_images = True
    needs_subscription = 'optional'
    max_age = 7  # days
    remove_empty_feeds = True
    extra_css = 'img { display: block; width: 75%; height: auto }'

    remove_tags = [
        dict(name='div', attrs={'class': 'External-ad'}),
        dict(name='header', attrs={'class': 'Header'}),
        dict(name='div', attrs={'class': 'Header-expanded'}),
        dict(name='div', attrs={'class': 'Overlay'}),
        dict(name='div', attrs={'class': 'Search-expanded'}),
        dict(name='section', attrs={'class': 'Site__footer'}),
        dict(name='div', attrs={'class': 'Toaster'}),
        dict(name='div', attrs={'class': 'fbc-badge'}),
        dict(name='div', attrs={'class': 'Posts-by-related-cat'}),
        dict(name='div', attrs={'class': 'finite-scroll'}),
        dict(name='div', attrs={'class': 'Sidebar'}),
        dict(name='div', attrs={'id': 'single-comments'}),
        dict(name='footer', attrs={'class': 'Single__footer'}),
        dict(name='div', attrs={'class': 'Social-share'}),
        dict(name='div', attrs={'class': 'mediaconnect-paywall'}),
        dict(name='svg', attrs={'class': 'icon'}),
        dict(name='figure', attrs={'class': 'wp-block-audio'}),
    ]

    remove_tags_after = [
        dict(name='div', class_='Single__content'),
    ]

    keep_only_tags = [
        dict(name='h1', class_='Single__title'),  # Title.
        dict(name='h1', class_='Longread__title'),  # Alt. title.
        dict(name='p', class_='Single__lead'),  # Lead text.
        dict(name='p', class_='Longread__lead'),  # Alt. lead text.
        dict(name='figure', class_='Single__thumbnail'),  # Image.
        dict(name='figure', class_='Longread__thumbnail'),  # Alt. image.
        # dict(name='p', class_='Meta__author'),  # Author.
        # dict(name='time', class_='Meta__updated'),  # Last updated.
        # Main article.
        dict(name='div', class_='sesamy-protected-content'),
        dict(name='div', class_='wp-block-core-paragraph'),
    ]

    def get_browser(self):
        br = BasicNewsRecipe.get_browser(self)
        if self.username and self.password:
            br.open('https://www.fokus.se/auth/logga-in')
            br.select_form(name='loginForm')
            br['j_username'] = self.username
            br['j_password'] = self.password
            br.submit()
        return br

    def get_web_sections(self, main_url: str) -> dict[str, str]:
        '''Return a dict of (1) section URL and (2) section name key-value pairs found at `main_url`.

        For example, if the Fokus website currently includes an 'Aktuellt' section, the dict should include an entry on
        the form: `{'https://www.fokus.se/aktuellt': 'Aktuellt'}`.

        Args:
            main_url (str): The entrypoint URL of the Fokus website.

        Yields:
            dict[str, str]: (1) URLs and (2) human-readable names of Fokus sections.
        '''
        self.log(f"Identifying all sections under '{main_url}'...")
        soup = self.index_to_soup(main_url)

        # Identify all unique <li> tags of class 'menu-item-type-taxonomy'. The class subsetting excludes sections that
        # are not suited for reading, e.g., the "Podcast" and "Läs E-Tidningen" sections.
        section_urls_and_names = {}
        for li_tag in soup.find_all('li', class_='menu-item-type-taxonomy'):
            # The <li> tag contains (should contain) an <a> anchor that in turn contains the URL and link name.
            a_tag = li_tag.find('a')
            url = a_tag.get('href').rstrip('/')
            section_name = a_tag.text.strip()

            if url in section_urls_and_names:
                # If this section URL has already been extracted from another <li> tag, it can be the case that the
                # section name differs within this duplicate pair. In this case, use whichever section name is longer.
                if len(section_name) >= len(section_urls_and_names[url]):
                    section_urls_and_names[url] = section_name

            self.log(f"Identified section '{section_name}' at URL '{url}'.")
            section_urls_and_names[url] = section_name

        self.log(f'Identified a total of {len(section_urls_and_names)} unique sections.')
        return section_urls_and_names

    def parse_article_blurb(self, article_blurb) -> dict[str, str, str, str] | None:
        '''Given a <article> tag of class 'Blurb', parse it into a dict.

        Args:
            article_blurb (Tag): An <article> tag hosting metadata and the URL of an article.

        Returns:
            dict[str, str, str, str]: A dict on a `{'url': str, 'title': str, 'description': str, 'date': str}` format.
        '''
        if a_tag := article_blurb.find('a', href=True):
            url = a_tag['href'].strip().rstrip('/')
            if url.startswith('/'):
                url = f'{self.main_url}{url}'

            if title_tag := a_tag.find('h2', {'class': 'Blurb__title'}):
                title = self.tag_to_string(title_tag).strip()
                if time_tag := a_tag.find('time', {'class': 'Blurb__date'}):
                    swedish_date_str = self.tag_to_string(time_tag).rstrip()

                    # Skip articles older than `self.max_age`.
                    datetime_str = time_tag['datetime']
                    datetime_time = datetime.strptime(datetime_str, '%Y-%m-%dT%H:%M:%S%z')
                    now = datetime.now(timezone.utc)
                    delta = now - datetime_time
                    if delta.days > self.max_age:
                        self.log.debug(f"\tSkipping article as it is too old: '{title}'")
                        return

                    desc = ''
                    if desc_tag := a_tag.find('div', {'class': 'Blurb__summary'}):
                        desc = self.tag_to_string(desc_tag).strip()
                        if in_cooperation_with_tag := a_tag.find('p', {'class': 'Blurb__meta'}):
                            desc += f' ({self.tag_to_string(in_cooperation_with_tag).strip()})'

                    return {'url': url, 'title': title, 'description': desc, 'date': swedish_date_str}
        return

    def _get_article_blurbs(self, soup) -> dict[str, dict[str, str, str, str]]:
        '''Given a Fokus webpage `soup`, return a dict of unique article entries found on the page.

        The key of a given entry in the output dictionary is the article URL. The corresponding value is a dictionary
        on a `{'url': str, 'title': str, 'description': str, 'date': str}` format.

        Args:
            soup (BeautifulSoup): The `bs4.BeautifulSoup` soup of a Fokus webpage.

        Returns:
            dict[str, dict[str, str, str, str]]: A dict with article URLs as keys and 'article dicts' as values.
        '''

        def _log(article) -> None:
            '''Log a digestible summary of the input `article` blurb.'''
            log_message = f"\t{article['title']} : {article['date']} : {article['url']}"
            if article.get('description'):
                log_message += f" : {article['description']}"
            self.log.debug(log_message)

        try:
            article_blurbs = soup.find_all('article', {'class': 'Blurb'})
        except AttributeError:
            article_blurbs = []

        if not article_blurbs:
            raise ValueError('Failed to identify any article blurbs.')

        parsed_blurbs = {}
        for article_blurb in article_blurbs:
            if article := self.parse_article_blurb(article_blurb):
                _log(article)
                # If an entry with the same URL already exists, keep whichever entry has the longer description.
                if article['url'] in article_blurbs:
                    if len(article['description']) <= len(parsed_blurbs[article['url']]['description']):
                        continue
                parsed_blurbs[article['url']] = article

        return parsed_blurbs

    def get_article_blurbs(self, sections: dict[str, str]) -> dict[str, dict[str, str, str, str]]:
        '''Create and return a dict of all unique article blurbs found in all `sections`.

        The key of a given entry in the output dictionary is the article URL. The corresponding value is a dictionary
        on a `{'url': str, 'title': str, 'description': str, 'date': str}` format.

        Args:
            sections (dict[str, str]): A dict on a `{section_url: section_name}` format.

        Returns:
            dict[str, dict[str, str, str, str]]: A dict with article URLs as keys and 'article dicts' as values.
        '''
        self.log(f'Identifying all articles under all {len(sections)} sections...')

        article_blurbs = {}
        for section_url, section_title in sections.items():
            try:
                section_soup = self.index_to_soup(section_url)
            except Exception:
                self.log.error(f"Failed to download section '{section_title}' via URL '{section_url}'")
                continue
            self.log(f"Identifying all articles under '{section_url}'...")
            for article_url, article_blurb in self._get_article_blurbs(section_soup).items():
                # If the article URL has already been encountered, keep only the article blurb with the longer
                # description string.
                if article_url not in article_blurbs:
                    article_blurbs[article_url] = article_blurb
                elif len(article_blurb['description']) > len(article_blurbs[article_url]['description']):
                    article_blurbs[article_url] = article_blurb

        self.log(f'A total of {len(article_blurbs)} articles were identified in the {len(sections)} sections.')
        return article_blurbs

    def assign_articles_to_sections(
        self,
        sections: dict[str, str],
        articles: dict[str, dict[str, str, str, str]],
    ) -> dict[str, list[dict[str, str, str, str]]]:
        '''Assign each article in `articles` to a section in `sections`.

        Args:
            sections (dict[str, str]): A dict of section URLs as keys and section titles as values.
            articles (dict[str, dict[str, str, str, str]]): A dict of article URLs as keys and article dicts as values.

        Returns:
            dict[str, list[dict[str, str, str, str]]]: A dict on a `{section_title: list[article_dict]}` format.
        '''
        self.log(f'Assigning each of the {len(articles)} articles to either of the {len(sections)} sections...')
        section_to_articles = {}
        for article_url, article_dict in articles.items():
            last_url = article_url
            while article_url not in sections and len(article_url) > len(self.main_url):
                article_url = article_url.rsplit('/', 1)[0]

                # Prevent an infinite loop.
                if article_url == last_url:
                    break
                last_url = article_url

            # If no section corresponding to the URL exists, default to the 'Home Page' section.
            section_title = sections[article_url] if article_url in sections else sections[self.main_url]
            if section_title not in section_to_articles:
                section_to_articles[section_title] = []
            section_to_articles[section_title].append(article_dict)

        # Log how many sections contained no articles younger than `self.max_age`.
        if diff := len(sections) - len(section_to_articles):
            self.log(f'{diff} sections contained no articles younger than {self.max_age} days.')

        return section_to_articles

    def parse_index(self):
        # Identify all sections in the web version of Fokus.
        sections = self.get_web_sections(self.main_url)

        # Add an entry for the start page.
        sections[self.main_url] = 'Home Page'

        # From the section URLs and the main URL, identify all unique articles.
        articles = self.get_article_blurbs(sections)
        if not articles:
            raise NoArticles(
                f"Could not find any articles. Either the '{self.main_url}' server is experiencing issues, in which "
                'case you should try again later, or the website format has changed and the recipe needs updating.'
            )

        # Assign each identified article to a section based on its URL.
        section_to_articles = self.assign_articles_to_sections(sections, articles)

        # Convert to the expected `list[tuple[str, dict[str, str, str, str]]]` format.
        feeds = list(section_to_articles.items())
        num_articles = sum(len(article_dicts) for article_dicts in section_to_articles.values())
        self.log(f'A total of {num_articles} articles belonging to {len(section_to_articles)} sections were kept.')

        return feeds
